Because of superior chemical stability and mechanical properties, polypropylene polymer films have been used widely as packaging materials for protection of articles from dust and dirt for example during transportation and displaying, and are generally used as sealed when the article is desirably protected air-tightly. Recently, there is a need for acceleration of bag making and packaging for improvement of packaging efficiency, and thus, for example, Japanese Patent Application Laid-Open No. 6-73132 (Patent Document 1) proposed a polypropylene polymer film superior in the balance between low-temperature heat-sealing efficiency and rigidity. Alternatively, Japanese Patent Application Laid-Open No. 10-259257 (Patent Document 2) discloses a polypropylene polymer film improved in rigidity in the high temperature range and elongation in the low temperature range for improvement of the processability in cold districts. Yet alternatively, Japanese Patent Application Laid-Open No. 2001-323229 (Patent Document 3) discloses a polypropylene film having a particular creep compliance at 90° C.